Fix memory leak in MacOS process handling.

runtime/bin/process_linux.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/process.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
@@ skipping 212 matching lines @@
     if (bytes_read != sizeof(msg)) {
       perror("Failed receiving notification message");
       exit(1);
     }
 
     close(write_out[1]);
     close(read_in[0]);
     close(read_err[0]);
     close(exec_control[0]);
 
-    dup2(write_out[0], STDIN_FILENO);
+    if (dup2(write_out[0], STDIN_FILENO) == -1) {

[Søren Gjesse, 2011/11/29 09:39:25]

As this is in the child process the output of these perror calls will not be
visible anywhere.

We should probably write something to the exec_control[1] file descriptor as
below and exit the child process.

[Mads Ager (google), 2011/11/29 10:10:13]

Yes, refactored the code after execvp into a ReportChildError helper and called
it from each of these.

+      perror("Failed to dup stdin");
+    }
     close(write_out[0]);
 
-    dup2(read_in[1], STDOUT_FILENO);
+    if (dup2(read_in[1], STDOUT_FILENO) == -1) {
+      perror("Failed to dup stdout");
+    }
     close(read_in[1]);
 
-    dup2(read_err[1], STDERR_FILENO);
+    if (dup2(read_err[1], STDERR_FILENO) == -1) {
+      perror("Failed to dup stderr");
+    }
     close(read_err[1]);
 
     execvp(path, const_cast<char* const*>(program_arguments));
     // In the case of failure write the errno and the OS error message
     // to the exec control pipe.
     int child_errno = errno;
     char* os_error_message = strerror(errno);
     ASSERT(sizeof(child_errno) == sizeof(errno));
     int bytes_written =
         FDUtils::WriteToBlocking(
@@ skipping 88 matching lines @@
   if (result == -1) {
     return false;
   }
   return true;
 }
 
 
 void Process::Exit(intptr_t id) {
   RemoveProcess(id);
 }